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EFFECTS OF A NORTH CENTRAL WASHINGTON WILDFIRE ON RUNOFF AND SEDIMENT PRODUCTION 1
Author(s) -
Helvey J. D.
Publication year - 1980
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1980.tb02441.x
Subject(s) - surface runoff , hydrology (agriculture) , infiltration (hvac) , environmental science , drainage basin , sediment , vegetation (pathology) , soil water , streamflow , geology , soil science , ecology , geography , geomorphology , geotechnical engineering , medicine , cartography , pathology , meteorology , biology
Runoff was measured from a 564‐ha catchment located on the Entiat Experimental Forest for nine years before a severe wild‐fire in 1970 destroyed the mixed conifer vegetation. Runoff records from the Chelan River (2 393 km 2 ) were used as control data for determining changes in water yield during the seven years following the fire. The first post‐fire year was a period of transition in which the soil profile retained more water than in previous years and measured runoff was 8.9 cm greater than the predicted value based on pre‐fire conditions. Runoff from the burned catchment during subsequent years was much greater than measured values before the fire. Measured minus predicted runoff, based on the pre‐fire calibration equation, varied from 10.7 cm during the dry year of 1977 to 47.2 cm during the abnormally wet year of 1972. Flow duration curves indicated that runoff at each percent value after the fire was at least double the comparable pre‐fire value. Sediment production increased dramatically after the fire because of increased flow rates, increased overland flow caused by reduced infiltration capacity, and mass soil movement. Sediment yield is beginning to decrease as stream channels become stabilized and vegetation on upper slopes improves infiltration capacity.